Window coverings have been available for many years based on a design incorporating a generally horizontal rigid head rail from which some form of mechanical blind or window covering or drapery is supported. It is necessary to provide some form of means for supporting the head rail in the desired location, usually in registration with or above a window. Typically, the head rail will be supported either on the window frame, the wall, or even the ceiling.
Various forms of support devices have been provided in the past. Some such support devices engage the head rail at either end. However, another class of support device provides two or more brackets which may be secured in position to the building fabric, and to which the head rail may be secured at spaced apart points intermediate its two ends. These brackets may have advantages in certain circumstances. It may improve the aesthetic appearance of the blind in some cases. In other cases, it may be more convenient to use such supporting brackets, rather than the end supporting devices used with some makes of blinds.
In the design of such supporting brackets, it is highly desirable that the brackets shall be so arranged that they may be secured to the building fabric, at spaced intervals, in a first operation. The brackets preferably incorporate some form of moveable clamping device interengageable with the head rail, so that in a second operation the head rail is simply raised into position, and the clamping devices are operated thereby clamping the head rail to the supporting brackets.
Various different forms of such supporting brackets incorporating such clamping devices are in fact known. It is however desirable from the viewpoint of economy that such supporting bracket devices shall be of extreme simplicity and design, and yet shall be functional so as to provide for a secure rigid clamping of the head rail to the support bracket when the clamping portion of the bracket is closed, and also to provide some form of interlock device holding the clamping portion of the bracket closed, so that it does not inadvertently become shaken loose and open up during use of the blind. If this should occur, the blind may then be simply free to fall down with the result that there may be possible damage to the blind, and even injury or at the very least inconvenience to a user of the blind.
In addition, it is desirable that it shall be provided with attachment means whereby it may be attached either to a vertical surface such as a window frame or a wall, or to a horizontal surface such as a ceiling, and that in either case the clamping device shall be readily operable. It is also desirable that it shall be of such a design that it is substantially concealed from view being either behind or above the head rail, in this way when viewed by persons standing in the room, the support brackets are virtually entirely out of sight.